Grass treatment machines are used for treating grass surfaces such as lawns, golf courses, playing fields and parkland. Various types of grass treatment machines exist and include, but are not limited to, mowers, rollers, scarifiers and spikers. As is known to those skilled in the art typically such machines include one or more grass treatment devices or heads, each device comprising one or a plurality of grass treatment tools. For many prior art grass treatment machines, such as, for example, those manufactured by John Deere, Toro, or Jacobsen, a plurality of grass treatment devices (typically two or three) are mounted on a given machine. A common configuration of three such grass treatment devices is such that they are mounted in a reverse echelon disposition: two grass treatment devices are mounted at the front of the machine with the third being mounted substantially immediately behind the first two.
Those skilled in the art will understand that in recent years improved varieties of grass have been bred for use as sports surfaces. In particular improved varieties of grass have been specifically bred for use on fairways and/or putting greens of golf courses and it is known that these grasses have become increasingly dense growing in comparison to earlier forms of grass. In relation to the improved grasses, generally known as ultra dense dwarf grasses, this means that the number of grass shoots per unit area is greater than with previous types of grass. Ultra dense dwarf grasses allow the grass to be cut to very low heights, which in turn allows greens and fairways to be faster, as regards the speed of travel of a golf ball disposed thereon, than has ever been previously possible. Examples of these new high-density grasses include cultivars of Bermuda Grass and Creeping Bent.
A disadvantage associated with the use of the new denser grass varieties are that they produce a large amount of organic matter and are also prone to lateral (as opposed to purely vertical) growth thereby leaving a so-called “nap”. These two conditions are exacerbated by the very dense or tight packed nature of the grass shoots.
In order to reduce the propensity for the grass to exhibit lateral growth a grass treatment tool known to those skilled in the art as a “groomer” has been developed. As those skilled in the art will appreciate a “groomer” typically comprises a toothed blade assembly that is made of a suitable metal and configured to lift up the grass blades such that they generally extend in direction that is closer to vertical than before grooming. A known type of groomer comprises 90 metal tipped blades spaced 5 mm apart that project axially out from the rotating shaft upon which they are mounted. The groomer works by disrupting the grass and an upper portion of the grass surface where it is growing via the action of the rotating metal tipped blades interacting with this surface. The action of these blades thins out the grass and thereby aids the grass blades to extend vertically as opposed to having a lateral component and furthermore reduces the tendency of the grass to exhibit lateral growth.
In contrast to a groomer tool a “brush” is a grass treatment tool that typically comprises a non-metallic blade configured to pick up and remove debris from the grass. Those skilled in the art will also appreciate that there are further kinds of treatment tools that are not cutting tools or rolling tools, a well known example being a tender conditioner unit (TCU).
Problems exist in trying to combine grooming and other grass treatment functions in a single grass treatment device as will now be described. Conventional grass treatment devices operate using a first treatment tool in the form of a roller or a so-called “skid plate” and a second treatment tool in the form of a roller. In between the first and second rollers there is typically a third treatment tool in the form of a cylindrically shaped cutting device known as a cutting reel. The first roller that is positioned at the front of a conventional grass treatment device acts to flatten the grass as it rolls over the grass surface. As the grass treatment device moves forwards the cutting reel then engages and cuts the grass blades that have been rolled by the first roller. Following cutting by the cutting reel the second roller that is positioned behind the cutting reel flattens the resultant cut and uncut grass stalks.
The distance between the first and second rollers is key as a significant problem with in particular the cutting of grass surfaces is the damage of a grass surface by the cutting of such a surface too deeply, this is known as scalping. Most normally caused by the action of the cutting reel digging into such a grass or turf surface and effectively up-rooting all or a portion of the grass in this region.
The cutting reel can be displaced out of position with respect to the grass surface when the surface changes pitch or becomes uneven. This is particularly the case when the first and second rollers which act to position the rotational cutting tool are on a portion of the cutting surface that is not at the same orientation as the region of the surface that the cutting reel is over. The distance between the first and second rollers is known as the “footprint” of the grass treatment device. In general therefore the shorter the distance between the first and second rollers (i.e. the smaller the footprint) the greater the cutting tool (or other treatment element which is positioned between the rollers) conforms to the contours of the grass surface which is being treated. Conversely the larger the distance between the rollers the greater the likelihood that the grass treatment tool positioned between the two rollers may be displaced from its optimum position with respect to the grass surface and so damage this surface when in use. As will be appreciated by those skilled in the art the cutting reel is not knocked out of position when the distance between the rollers is too great. What occurs is the scalping referred to earlier. In effect the reel cuts deep in to the turf canopy injuring the grass.
In view of the increase in use of the ultra dense dwarf grasses mentioned above there is increasingly a need to groom grass before it is cut so as to enable the grass to be cut more effectively. However prior art grass treatment devices known to the inventors of the present invention basically either comprise (a) two rollers and a cutting tool or (b) comprise two rollers, a cutting tool and a groomer tool located in between the two rollers. The problem with these known devices are as follows.
For optimum grass to be provided a given owner of a grassed area, such as a golf course, would need a type (a) device and a type (b) device. A problem with this is that requiring both types of devices is expensive. If the given owner cannot afford or justify such expenditure then the grass owner has to choose between purchasing a device that does not groom (type a) or a type (b) device. As will be understood by those skilled in the art known type (b) devices are more expensive than type (a) devices. Furthermore prior art type (b) devices have a greater footprint than type (a) devices in view of the fact that a groomer tool (or another tool, such as, for example, a brush) is disposed between the front roller and the cutting tool element.
In conclusion it is known to provide a grass treatment device that cuts and grooms, but this means that the device cannot safely cut grass as low without scalping.
In view of the above there is a need to provide an improved grass treatment device that enables multiple grass treatment functions, in particular, but not exclusively grooming and cutting, to be readily deployed by a single grass treatment device.